What is likely happening
A discharging pressure-relief valve is a safety device doing its job. Frequent discharge points to a waterlogged expansion tank, a failing fill valve, or an overpressure or overheating condition that must be diagnosed. Never cap, plug, or block a relief valve.
What you can safely check
- Read the pressure and temperature gauges and write the numbers down.
- Look for water at the relief valve discharge pipe and note how often it happens.
- Keep people clear of the discharge outlet; the water can be scalding.
What an inspector will look at
- Relief valve rating, set pressure and condition
- Expansion tank charge
- Pressure-reducing fill valve
- Operating and high-limit controls
Does this affect compliance?
Relief valves are among the first things checked at a required boiler inspection. A valve that is leaking, undersized, or piped incorrectly is typically written up as a defect.
When it becomes urgent
Shut the boiler down and call for service immediately if pressure keeps climbing or the gauge reads at or above the relief valve setting.
We can help with this
Boiler inspection is something Insparisk does nationwide. To see the local rules for your building, open this in the interactive Problem Solver.
Request boiler inspectionTalk to an advisorGeneral guidance only, not a substitute for a licensed inspection or emergency services. For any gas odor, carbon monoxide alarm, fire, or trapped occupant, call 911 first.